U.S. patent application number 13/935271 was filed with the patent office on 2015-01-08 for pulse separated direct inlet axial automotive turbine.
The applicant listed for this patent is Ford Global Technologies, LLC. Invention is credited to John Christopher Riegger, Robert Andrew Wade.
Application Number | 20150007800 13/935271 |
Document ID | / |
Family ID | 51264339 |
Filed Date | 2015-01-08 |
United States Patent
Application |
20150007800 |
Kind Code |
A1 |
Wade; Robert Andrew ; et
al. |
January 8, 2015 |
PULSE SEPARATED DIRECT INLET AXIAL AUTOMOTIVE TURBINE
Abstract
Systems and methods for operating a turbocharged engine are
described. In one example, a system comprises a cylinder head
having a first and second exhaust duct separately coupled to first
and second groups of cylinders, each of the first and second
exhaust ducts leading to an exhaust driven turbine mounted inside
the cylinder head on a bearing, the bearing located within a
bearing housing supported by the cylinder head. In this way,
exhaust pulses remain separate up to the turbine mounted inside the
cylinder head.
Inventors: |
Wade; Robert Andrew;
(Plymouth, MI) ; Riegger; John Christopher; (Ann
Arbor, MI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Ford Global Technologies, LLC |
Dearborn |
MI |
US |
|
|
Family ID: |
51264339 |
Appl. No.: |
13/935271 |
Filed: |
July 3, 2013 |
Current U.S.
Class: |
123/568.14 |
Current CPC
Class: |
F02F 2001/4278 20130101;
Y02T 10/12 20130101; F02M 26/14 20160201; Y02T 10/144 20130101;
F02F 1/4264 20130101; F02B 37/18 20130101; F02C 6/12 20130101; F05D
2220/40 20130101; F01N 13/10 20130101 |
Class at
Publication: |
123/568.14 |
International
Class: |
F02M 25/07 20060101
F02M025/07 |
Claims
1. A system, comprising: a cylinder head having a first and second
exhaust duct separately coupled to first and second groups of
cylinders, each of the first and second exhaust ducts leading to an
exhaust driven turbine mounted inside the cylinder head on a
bearing, the bearing located within a bearing housing supported by
the cylinder head.
2. The system of claim 1 wherein the cylinder head further
comprises cooling passages adjacent the turbine and a wastegate gas
passage.
3. The system of claim 1 wherein the turbine is an axial, mixed
flow or radial turbine, and where the turbine includes one or more
stages, and where the stages included one or more stator
stages.
4. The system of claim 3, where the stator stages are unique vanes
or part of the cylinder head.
5. The system of claim 1, wherein outlets of each of the first and
second exhaust ducts form a semi-circular cross-sectional coupling
with a gas collector of the turbine.
6. The system of claim 5 wherein two semi-circular cross-sections
of each of the first and second outlets are positioned relative to
one another to form an annular combined outlet.
7. The system of claim 1, further comprising at least a third
exhaust duct separately coupled to a third group of cylinders.
8. The system of claim 7, where each of the groups of cylinders
comprise one cylinder, and each of the exhaust ducts couple to a
gas collector of the turbine.
9. The system of claim 8, where each of the exhaust ducts comprise
arc-shaped outlets that combine to form an annular combined
outlet.
10. A turbocharged engine comprising: a cylinder head forming two
or more exhaust ducts, each with an outlet terminus at a turbine
wheel or collector, an opening of the outlet terminus of a first
exhaust duct being a semi-circular annular shape within 5.degree.
of a half-circle and an opening of the outlet terminus of a second
exhaust output line being a semi-circular annular shape within
5.degree. of a half-circle, the outlet termini positioned opposite
one another to form a circular annulus.
11. The turbocharged engine of claim 10 where the cylinder head
includes exhaust ports for two or more engine cylinders.
12. The turbocharged engine of claim 11 where the engine cylinders
are placed in an inline, opposed or V configuration.
13. The turbocharged engine of claim 11 further comprising an axial
turbine at least partially rotatably mounted in the cylinder
head.
14. The turbocharged engine of claim 13 wherein rotor and stator
stages of the axial turbine are positioned in the cylinder
head.
15. The turbocharged engine of claim 14 wherein the first exhaust
duct is coupled to outer engine cylinders, and the second exhaust
duct is coupled to inner engine cylinders.
16. The turbocharged engine of claim 15 wherein the cylinder head
further comprises a wastegate passage.
17. The turbocharged engine of claim 16 where the turbine is
coupled to one or more compressors via a common shaft.
18. A method, comprising: combining, in a cylinder head, exhaust
gas from inner inline cylinders of an engine to a first
semi-circular annular exit; combining, in the cylinder head,
exhaust gas from outer inline cylinders of an engine to a second
semi-circular annular exit positioned opposite the first
semi-circular annular exit; and directing exhaust gas out of the
first and second exits through an axial turbine with bearings
mounted in the cylinder head.
19. The method of claim 18, where the axial turbine is coupled to a
radial compressor through a common shaft.
20. The method of claim 19, further comprising adjusting a
wastegate valve to adjust flow through a wastegate line positioned
in the cylinder head.
Description
BACKGROUND AND SUMMARY
[0001] Turbocharging an internal combustion engine can reduce
external emissions and increase the specific power output of the
engine, as exhaust departing from the engine cylinders may be
directed through a turbine and the resulting energy used to power a
compressor. One example configuration integrates the exhaust ports
leading from the engine cylinders as well as the turbine housing
into the cylinder head itself.
[0002] The inventors herein have recognized that achieving exhaust
pulse separation enables an exhaust cam duration beneficial to
improving fuel consumption, improving low engine speed torque, and
achieving better specific power output that current designs. A
turbine integrated into the cylinder head will simultaneously
reduce cost and decrease the engine footprint. For example, an
integrated turbine may decrease the overall size of the system
while increasing the efficiency of the engine and the specific
power. An integrated axial turbine may also have a faster transient
response than a corresponding radial turbine. However, to maintain
efficient combustion with long exhaust cam events, residual exhaust
gas must be prevented from entering the engine cylinders during an
exhaust blowdown event when multiple exhaust valves are open. This
is accomplished with full pulse separation of the exhaust gas up to
the point where the exhaust gas enters the turbine. In an I-4
engine with a conventional firing order, for example, this may be
accomplished by joining the exhaust ports exiting cylinders 1 and 4
together into a first exhaust duct and joining the exhaust ports
exiting cylinders 2 and 3 together into a second exhaust duct. The
outlets of the two ducts may be connected to the inlet of the
turbine.
[0003] However, the inventors have also recognized that the current
manifold designs that achieve full pulse separation are targeted to
radial turbines and may not be applicable to systems that use axial
turbines. Incorporating such manifolds may require an external
turbocharger, which would increase cost and have a worse transient
response.
[0004] The above issues may be at least partially addressed, in one
example, by a system comprising a cylinder head having a first and
second exhaust duct separately coupled to first and second groups
of cylinders, each of the first and second exhaust ducts leading to
an exhaust driven turbine mounted inside the cylinder head on a
bearing, the bearing located within a bearing housing supported by
the cylinder head.
[0005] In this way, the system may allow pulse separation of
exhaust gas exiting the cylinders all the way to an inlet of a
turbine, while maintaining a compact configuration. Separating
exhaust gas pulses in this way may result in an increase in the
efficiency of exhaust gas delivery to a turbine.
[0006] Further, the outlets of each of the first and second ducts
may form a semi-circular cross-sectional coupling with a gas
collector of the turbine, and the two semi-circular cross-sections
of each of the first and second outlets may be positioned relative
to one another to form an annular combined outlet. In this way, the
stator and rotor stages of an axial turbine may be inserted into
the opening created in the cylinder head.
[0007] In another example, a turbocharged engine comprising a
cylinder head forming two or more exhaust ducts, each with an
outlet terminus at a turbine wheel or collector, an opening of the
outlet terminus of a first exhaust duct being a semi-circular
annular shape and an opening of the outlet terminus of a second
exhaust output line being a semi-circular annular shape, the outlet
termini positioned opposite one another to form a circular annulus.
Further, the first exhaust duct may be coupled to outer engine
cylinders, and the second exhaust duct may be coupled to inner
engine cylinders. In this way, pulse separation may be achieved up
to a turbine inserted into the cylinder head within the circular
annulus.
[0008] In another example, a method, comprising combining, in a
cylinder head, exhaust gas from inner inline cylinders of an engine
to a first semi-circular annular exit, combining, in the cylinder
head, exhaust gas from outer inline cylinders of an engine to a
second semi-circular annular exit positioned opposite the first
semi-circular annular exit, and directing exhaust gas out of the
first and second exits through an axial turbine with bearings
mounted in the cylinder head. This method may further comprise
adjusting a wastegate valve to adjust flow through a wastegate line
positioned in the cylinder head. In this way, the flow of exhaust
gas may be controlled within the cylinder head to achieve optimal
engine performance.
[0009] In other embodiments, the exhaust ducts may enter a turbine
collector at a variety of angles to the turbine to achieve the
desired relative gas velocity. The outlet terminus of the exhaust
ducts may be arranged to cover any variety of sectors of the
turbine ranging from half of the turbine circumference to a very
small portion of the turbine circumference. This sector
configuration may include a unique sector for each cylinder or for
groups of cylinders. In this way, pulse separation may be achieved
all the way to the turbine collector without combining exhaust
pulses.
[0010] It should be understood that the summary above is provided
to introduce in simplified form a selection of concepts that are
further described in the detailed description. It is not meant to
identify key or essential features of the claimed subject matter,
the scope of which is defined uniquely by the claims that follow
the detailed description. Furthermore, the claimed subject matter
is not limited to implementations that solve any of the
disadvantages noted above or in any part of this disclosure.
BRIEF DESCRIPTION OF FIGURES
[0011] FIG. 1 shows a schematic diagram of a turbocharged engine in
accordance with the present disclosure.
[0012] FIG. 2A shows a perspective view of a cylinder head in
accordance with the present disclosure.
[0013] FIG. 2B shows a perspective view of a cylinder head coupled
to a bearing housing.
[0014] FIG. 3 shows a perspective view of an exhaust manifold and
turbocharger assembly.
[0015] FIG. 4 shows a perspective view of a turbocharger assembly
equipped with an oil and coolant supply.
[0016] FIG. 5A shows a perspective view of an example exhaust
manifold.
[0017] FIG. 5B shows a perspective view of the input end of an
example turbine.
[0018] FIGS. 2A, 2B, 3 and 5A-B are drawn approximately to scale,
but other dimensions may be used.
DETAILED SPECIFICATION
[0019] The following description relates to systems and methods for
operating an engine including a turbocharger system, for example as
shown in FIG. 1.
[0020] FIG. 1 is a schematic diagram showing an example engine 10,
which may be included in a propulsion system of an automobile. The
engine 10 includes cylinder head 175, which is shown with four
cylinders 30. However, other numbers of cylinders may be used in
accordance with the current disclosure. Engine 10 may be controlled
at least partially by a control system including controller 12, and
by input from a vehicle operator 132 via an input device 130. In
this example, input device 130 includes an accelerator pedal and a
pedal position sensor 134 for generating a proportional pedal
position signal PP. Each combustion chamber (e.g., cylinder) 30 of
engine 10 may include combustion chamber walls with a piston (not
shown) positioned therein. The pistons may be coupled to a
crankshaft 40 so that reciprocating motion of the piston is
translated into rotational motion of the crankshaft. Crankshaft 40
may be coupled to at least one drive wheel of a vehicle via an
intermediate transmission system (not shown). Further, a starter
motor may be coupled to crankshaft 40 via a flywheel to enable a
starting operation of engine 10.
[0021] Combustion chambers 30 may receive intake air from intake
manifold 44 via intake passage 42 and may exhaust combustion gases
via exhaust passage 48. Intake manifold 44 and exhaust manifold 46
can selectively communicate with combustion chamber 30 via
respective intake valves and exhaust valves (not shown). In some
embodiments, combustion chamber 30 may include two or more intake
valves and/or two or more exhaust valves.
[0022] Fuel injectors 50 are shown coupled directly to combustion
chamber 30 for injecting fuel directly therein in proportion to the
pulse width of signal FPW received from controller 12. In this
manner, fuel injector 50 provides what is known as direct injection
of fuel into combustion chamber 30. The fuel injector may be
mounted in the side of the combustion chamber or in the top of the
combustion chamber, for example. Fuel may be delivered to fuel
injector 50 by a fuel system (not shown) including a fuel tank, a
fuel pump, and a fuel rail. In some embodiments, combustion
chambers 30 may alternatively, or additionally, include a fuel
injector arranged in intake manifold 44 in a configuration that
provides what is known as port injection of fuel into the intake
port upstream from each combustion chamber 30.
[0023] Intake passage 42 may include throttle 21 and 23 having
throttle plates 22 and 24, respectively. In this particular
example, the position of throttle plates 22 and 24 may be varied by
controller 12 via signals provided to an actuator included with
throttles 21 and 23. In one example, the actuators may be electric
actuators (e.g., electric motors), a configuration that is commonly
referred to as electronic throttle control (ETC). In this manner,
throttles 21 and 23 may be operated to vary the intake air provided
to combustion chamber 30 among other engine cylinders. The position
of throttle plates 22 and 24 may be provided to controller 12 by
throttle position signal TP. Intake passage 42 may further include
a mass air flow sensor 120 and a manifold air pressure sensor 122
for providing respective signals MAF (mass airflow) and MAP
(manifold air pressure) to controller 12.
[0024] Exhaust passage 48 may receive exhaust gases from cylinders
30. Cylinders 30 may be coupled to exhaust passage 48 through a
plurality of valves and ports described further below and in
reference to FIG. 3. The plurality of valves may open to allow
exhaust to exit cylinders 30 and enter exhaust ports 47, which
further direct exhaust gas to exhaust passage 48. In the example
depicted in FIG. 1, the exhaust ports 47 are located inside of
cylinder head 175. It will be appreciated that such a conformation
may be referred to as an "integrated exhaust manifold" wherein
exhaust manifold 46 is located inside cylinder head 175.
[0025] Exhaust gas sensor 128 is shown coupled to exhaust passage
48 upstream of emission control device 78. Sensor 128 may be
selected from among various suitable sensors for providing an
indication of exhaust gas air/fuel ratio such as a linear oxygen
sensor or UEGO (universal or wide-range exhaust gas oxygen), a
two-state oxygen sensor or EGO, a NOx, HC, or CO sensor, for
example. Emission control device 78 may be a three way catalyst
(TWC), NOx trap, various other emission control devices, or
combinations thereof. Exhaust temperature may be measured by one or
more temperature sensors (not shown) located in exhaust passage 48.
Alternatively, exhaust temperature may be inferred based on engine
operating conditions such as speed, load, air-fuel ratio (AFR),
spark retard, etc.
[0026] Controller 12 is shown in FIG. 1 as a microcomputer,
including microprocessor unit 102, input/output ports 104, an
electronic storage medium for executable programs and calibration
values shown as read-only memory chip 106 in this particular
example, random access memory 108, keep alive memory 110, and a
data bus. Controller 12 may receive various signals from sensors
coupled to engine 10, in addition to those signals previously
discussed, including measurement of inducted mass air flow (MAF)
from mass air flow sensor 120; engine coolant temperature (ECT)
from temperature sensor 112, shown schematically in one location
within the engine 10; a profile ignition pickup signal (PIP) from
Hall effect sensor 118 (or other type) coupled to crankshaft 40;
the throttle position (TP) from a throttle position sensor, as
discussed; and absolute manifold pressure signal, MAP, from sensor
122, as discussed. Engine speed signal, RPM, may be generated by
controller 12 from signal PIP. Manifold pressure signal MAP from a
manifold pressure sensor may be used to provide an indication of
vacuum, or pressure, in the intake manifold 44. Note that various
combinations of the above sensors may be used, such as a MAF sensor
without a MAP sensor, or vice versa. During stoichiometric
operation, the MAP sensor can give an indication of engine torque.
Further, this sensor, along with the detected engine speed, can
provide an estimate of charge (including air) inducted into the
cylinder. In one example, sensor 118, which is also used as an
engine speed sensor, may produce a predetermined number of equally
spaced pulses for each revolution of the crankshaft 40. In some
examples, storage medium read-only memory 106 may be programmed
with computer readable data representing instructions executable by
processor 102 for performing the methods described below as well as
other variants that are anticipated but not specifically
listed.
[0027] Engine 10 may further include a compression device such as a
turbocharger or supercharger including at least a compressor 60
arranged upstream of intake manifold 44. For a turbocharger,
compressor 60 may be at least partially driven by a turbine 62,
via, for example shaft 160, or other coupling arrangement. The
turbine 62 may be couple exhaust manifold 46 to exhaust passage 48,
for example via an integrated exhaust manifold, as described above.
Various arrangements may be provided to drive the compressor. For a
supercharger, compressor 60 may be at least partially driven by the
engine and/or an electric machine, and may not include a turbine.
Thus, the amount of compression provided to one or more cylinders
of the engine via a turbocharger or supercharger may be varied by
controller 12. In some cases, the turbine 62 may drive, for
example, an electric generator, to provide power to a battery via a
turbo driver. Power from the battery may then be used to drive the
compressor 60 via a motor. Further, a sensor 123 may be disposed in
intake manifold 44 for providing a BOOST signal to controller
12.
[0028] Further, exhaust passage 48 may include wastegate 26 for
diverting exhaust gas away from turbine 62. In some embodiments,
wastegate 26 may be a multi-staged wastegate, such as a two-staged
wastegate with a first stage configured to control boost pressure
and a second stage configured to increase heat flux to emission
control device 78. Wastegate 26 may be operated with an actuator
150, which, for example, may be an electric actuator including
permanent magnets. In various embodiments, actuator 150 may be an
electric motor, a pressure controlled actuator or a vacuum
controlled actuator. Additional detail regarding wastegate 26 and
actuator 150 will be presented below. Intake passage 42 may include
a compressor bypass valve 27 configured to divert intake air around
compressor 60. Wastegate 26 and/or compressor bypass valve 27 may
be controlled by controller 12 via actuators (e.g., actuator 150)
to be opened when a lower boost pressure is desired, for
example.
[0029] Intake passage 42 may further include charge air cooler
(CAC) 80 (e.g., an intercooler) to decrease the temperature of the
turbocharged or supercharged intake gases. In some embodiments,
charge air cooler 80 may be an air to air heat exchanger. In other
embodiments, charge air cooler 80 may be an air to liquid heat
exchanger.
[0030] An exhaust gas recirculation (EGR) system may route a
desired portion of exhaust gas from exhaust passage 48 to intake
passage 42 via EGR passage 140. The amount of EGR provided to
intake passage 42 may be varied by controller 12 via EGR valve 142.
Further, an EGR sensor (not shown) may be arranged within the EGR
passage and may provide an indication of one or more of pressure,
temperature, and concentration of the exhaust gas. Alternatively,
the EGR may be controlled through a calculated value based on
signals from the MAF sensor (upstream), MAP (intake manifold), MAT
(manifold gas temperature) and the crank speed sensor. Further, the
EGR may be controlled based on an exhaust O.sub.2 sensor and/or an
intake oxygen sensor (intake manifold). Under some conditions, the
EGR system may be used to regulate the temperature of the air and
fuel mixture within the combustion chamber. FIG. 1 shows a high
pressure EGR system where EGR is routed from upstream of a turbine
of a turbocharger to downstream of a compressor of a turbocharger.
In other embodiments, the engine may additionally or alternatively
include a low pressure EGR system where EGR is routed from
downstream of a turbine of a turbocharger to upstream of a
compressor of the turbocharger.
[0031] FIG. 2A shows a perspective view of a cylinder assembly 210
in accordance with the present disclosure. FIG. 2B shows a
perspective view of the cylinder assembly 210 depicted in FIG. 2A
coupled to turbocharger 300. Cylinder assembly 210 includes
cylinder head 175 which may attach to a cylinder block (not shown)
which includes a plurality of combustion chambers (e.g., cylinders)
30 of engine 10 that may each include combustion chamber walls with
a piston (not shown) positioned therein. The cylinders may be
positioned in an inline configuration such that the cylinders are
aligned along the central axis of the cylinder head. Alternatively,
the cylinders may be aligned in a V-configuration, a flat
configuration or other suitable configuration. When attached to a
cylinder block, the depicted cylinder head 175 may form 4
cylinders. In another example, the cylinder assembly may utilize an
alternate number of cylinders, such as 3 cylinders. Cylinder head
175 may be cast out of a suitable material such as iron or
aluminum. The cylinder head may include numerous components not
depicted in this example perspective, including camshafts, intake
and exhaust valves, spark plugs, fuel injectors 50, temperature
sensor 112, other suitable mechanical components and other suitable
sensors and actuators, such as shown in FIG. 1, for example.
[0032] As depicted, cylinder head 175 includes four perimeter
walls. The walls include a first side wall 211, a second side wall
212, a rear end wall 213, and a front end wall 214. First sidewall
211 may be configured as the intake side of the cylinder head
cooperating with intake valves of the engine, and may include
components such as valves and ports as needed to interface with
intake manifold 44 and to allow or restrict the flow of intake air
into the cylinder head. Front end wall 214 may include components
as needed to interface with crankshaft 40 and to allow the coupling
of crankshaft 40 to the pistons included in cylinder head 175.
Second side wall 212 may be configured as the exhaust side of the
cylinder head cooperating with exhaust valves of the engine and may
include components such as one or more mounting bolt boss 252 or
other suitable devices for mounting bearing housing 280 directly to
the cylinder head. In this example configuration, the turbocharger
assembly may be directly coupled to the cylinder head.
Alternatively, the turbocharger assembly may be indirectly coupled
to the cylinder head. The turbocharger assembly and possible
configurations thereof are discussed further below and with regard
to FIG. 3. Cylinder head 175 may also include a plurality of
cylinder closure portions 218.
[0033] Cylinder head 175 may include one or more cooling jackets.
For example, a first cooling jacket may be located between exhaust
manifold 46 and the interface between cylinder head 175 and the
cylinder block. A second cooling jacket may be located on the
opposite side of the exhaust manifold as the first cooling jacket.
The first and second cooling jackets may be coupled together by a
flow passage. In some examples, the first and second cooling
jackets may be coupled to a turbine cooling jacket through a flow
passage. In another example, the first and second cooling jackets
may be separate and operate with different coolants or different
supplies of the same coolant. In another example, a first cooling
jacket may be located on the intake side of the plurality of
cylinders, and a second cooling jacket located on the exhaust side
of the cylinders. The two cooling jackets may have substantially
different cooling capacities, and may be coupled to a cooling water
system including a radiator, coolant pump driven by the engine,
thermostat, etc. In one example, a cooling jacket located on the
exhaust side of the cylinders may have a higher cooling capacity
than the cooling jacket on the intake side of the cylinders, for
example via a higher flow rate, increased surface area, etc. In
another example, the cooling jacket located on the intake side of
the cylinders may have a higher cooling capacity than the cooling
jacket on the exhaust side of the cylinders.
[0034] Cylinder head 175 includes an exhaust manifold 46. The
components of the exhaust manifold will be discussed further below
and with regard to FIGS. 3, 5A and 5B, and include a plurality of
exhaust ports 47 coupled to cylinders 30, and a plurality of
exhaust ducts 310 coupled to exhaust ports 47. Exhaust ducts 310
may discharge exhaust gas into exhaust collector 320. Each cylinder
may have an intake and exhaust valve. In some cases, each cylinder
may include two or more intake valves and two or more exhaust
valves. Each intake valve and exhaust valve may be operated by an
intake cam and an exhaust cam, respectively. In another example,
the intake and exhaust valves may be actuated by a valve coil and
armature assembly.
[0035] One or more of exhaust ducts 310 may be further configured
to include a wastegate 26 (not shown). Alternatively, wastegate 26
may be included in exhaust collector 320. Wastegate 26 may be
configured to control the amount of exhaust gas that bypasses the
turbine. Wastegate 26 may be actuated by wastegate actuator 150.
Wastegate actuator 150 may be mounted onto cylinder head 175 or
onto bearing housing 280. The wastegate may be actuated in response
to the pressure in exhaust collector 275 exceeding a threshold as
measured by a pressure sensor (nor shown) or in response to MAP
sensor measurements above the required value to deliver the desired
torque. Wastegate actuator 150 may be activated or deactivated in
response to signals sent by controller 12. Activation of wastegate
26 allows exhaust gas to enter exhaust outlet 290 and further to an
exhaust bypass line (not shown), allowing the exhaust gas to bypass
the turbocharger assembly. Exhaust outlet 290 may be included in
bearing housing 280. The wastegate passage may have an entry
coupled to the cylinder head and an exit coupled to a hot gas
collector within the bearing housing.
[0036] Bearing housing 280 may be attached to cylinder head 175 via
mounting bolts 250 and mounting bolt boss 252, or through other
appropriate attachment devices. As depicted in FIG. 2B, the direct
coupling of bearing housing 280 to cylinder head 175 in this
configuration allows for turbine 62 to be situated proximal to
exhaust collector 320, allowing for conservation of exhaust gas
energy within engine 10. As discussed further below and in regards
to FIG. 3, this example configuration may allow for some of the
components of the turbocharger assembly, such as the rotor stage
and stator stage to be directly coupled to the cylinder head,
minimizing the amount of space taken up by the turbocharger
assembly. Bearing housing 280 may include other components as
needed for mounting components of the turbocharger assembly or
components as needed to mount additional sensors or actuators. For
example a mounting boss for an exhaust gas oxygen sensor may be
included in bearing housing 280.
[0037] FIGS. 3 and 4 show perspective views of the turbocharger
assembly in accordance with the current disclosure. FIG. 3 shows a
perspective view of exhaust ports 47 and exhaust ducts 310 and
turbocharger assembly 300 in accordance with the current
disclosure. FIG. 3 shows an example integrated exhaust manifold 46
for a 4 cylinder engine, but may include fewer or additional
cylinders, for example 2, 3, 5 or 6 cylinders. FIG. 4 shows a side
view of the turbocharger assembly 300 in accordance with the
present disclosure. Exhaust manifold 46 may be included in cylinder
head 175 as depicted in FIG. 2. Each cylinder 30 may have one or
more exhaust valves coupled between the cylinder and an exhaust
port 47. Exhaust ports 47 may be coupled to exhaust ducts 310. The
exhaust ports receive exhaust gas released from the cylinders
during engine operation. An exhaust runner may be formed at the
merger of exhaust ports from adjacent cylinders or from cylinders
that are not adjacent. For example, in an I4 engine configuration,
it may be advantageous to merge exhaust ports from cylinders 2 and
3 into a first exhaust runner and to merge exhaust ports from
cylinders 1 and 4 into a second exhaust runner. This configuration
may allow for exhaust pulse separation to be maintained for this
example engine configuration.
[0038] Exhaust ducts 310 may terminate into one or more openings at
the mouth of exhaust collector 320. One or more exhaust runners may
also include a wastegate passage 26 as described above. Under a
condition where exhaust pressure in exhaust collector 320 exceeds a
predetermined threshold, controller 12 may activate wastegate
actuator 150, allowing exhaust gas to flow through wastegate 26 and
into exhaust outlet 290, where it may be routed through an exhaust
bypass line, bypassing the turbocharger assembly.
[0039] In another example, one or more exhaust ducts 310 may direct
exhaust gas back to intake manifold 44 for re-entry to engine 10 as
part of a dedicated exhaust gas recirculation system. In yet
another example, a valve or other switching mechanism may divert
exhaust gas flow from one or more exhaust ducts 310 to intake
manifold 44 under a first condition, and to exhaust gas collector
320 under a second condition.
[0040] Exhaust gas collector 320 may be included in bearing housing
280. In another example, the exhaust gas collector may be included
in cylinder head 175. In yet another example, the exhaust gas
collector may be a separate component coupled between the cylinder
head and bearing housing, or may be composed of portions of both
the cylinder head and bearing housing. Exhaust gas may be directed
from exhaust gas collector 320 to turbocharger assembly 300.
[0041] Turbocharger assembly 300 may include bearing housing 280,
turbine housing 285, turbine 62, compressor housing 335, compressor
60, as well as components thereof, some of which are discussed
further below and in regard to FIG. 4. Exhaust gas collector 320
may be fabricated as a part of bearing housing 280 or may be
fabricated separately. In the example system depicted in FIGS. 3
and 4, turbine 62 is an axial turbine, but may also be a radial
turbine or a mixed flow turbine. The turbine may be of a single
stage or of multiple stages. The stator may also be of single or
multiple stages. For an axial turbine, the flow of exhaust gas
approaching the turbine rotor blades may be described as running
substantially axially. Herein, "substantially axially" is used to
mean that the flow of exhaust gas through the turbine is parallel
to the turbine shaft. The exhaust inlet may be configured to direct
exhaust gas in a substantially axial direction to the turbine. In
another example, turbine 62 may be configured to be a radial
turbine, where the flow of exhaust gas approaching the turbine
rotor blades runs substantially radially, and where the exhaust
inlet is configured to direct exhaust gas in a direction
substantially perpendicular to the turbine shaft. In another
example, the exhaust gas may approach the turbine in a geometry
between axial and radial, e.g. a mixed flow turbine.
[0042] Bearing housing 280 may be fabricated from cast iron or
other suitable materials that have a high thermal distortion
resistance, or other materials suitable for exposure to the high
temperatures experienced during engine operation. Turbine stator
322 may be fabricated by welding sheets of stamped metal into
appropriate shapes and configurations, or may be fabricated by
casting material into an appropriate shape. Turbine collector 350
may be fabricated as a part of bearing housing 280, which may also
be fabricated from cast iron or other suitable materials that have
a high temperature capability. In this example, a further liquid
cooling system may not be included.
[0043] Turbine housing 285 may also be fabricated from materials
such as aluminum, and may thus further include a liquid cooling
system be included in or surrounding the housing. As shown in FIG.
4, oil and coolant supply 401 may be supplied to bearing housing
280 through passages 402 integrated into the collector and bearing
housing. Cooling may also be supplied with external coolant tubes
and hoses. In another example, turbine housing 285 may be
fabricated as a separate piece from bearing housing 280 and coupled
the bearing housing with bolts or other suitable fasteners.
[0044] Turbocharger assembly 300 includes stator 322, rotor 325,
turbine 62, compressor 60, compressor housing 335 and bearing
housing 280. Turbine 62 may be coupled to compressor 60 via shaft
160. Stator 322 may be placed within cylinder head 175. In one
example, stator 322 may be fabricated from welded pieces of
stainless steel sheet metal. Stator 322 may be cast as a separate
piece or cast of multiple pieces. Stator 322 may be attached with
various schemes, including snap-in-place, press-in-place, or
mechanically attached with bolts or v-bands. The stator may be
designed to fit into a complimentary stator mount within the
cylinder head that both retains the stator and prevents its
rotation. In some examples, the cylinder head may act as the
stator, and configured to steer and accelerate the flow of exhaust
gas to a desired incidence angle and velocity.
[0045] Rotor 325 may also be placed within cylinder head 175. In
one example, bearing housing 280 may be mounted via one or more
dowels. The bearing housing may have a cooling passage or passages
routed near the dowel mounts in order to minimize thermal
distortion of the bearing housing and to ensure the rotor remains
in place and maintains sufficient distance between the rotor blades
and the housing so as not to incur blade rubbing and to maintain a
minimum clearance necessary to preserve turbine efficiency.
[0046] Turbocharger assembly 300 may also include a gas collector
350 following the turbine. Gas collector 350 may include a
torroidial passage, wherein exhaust gas may be routed from the
turbine to a single outlet part of the bearing housing. Gas
collector 350 may further merge with exhaust outlet 290, or may
direct exhaust gas to an emissions control device or an exhaust gas
recirculation system.
[0047] The bearing housing may include a plurality of bearings that
may be designed for both a thrust and a radial load. The bearings
may be journal bearings, ball bearings, needle bearings, air
bearings, or other appropriate bearings. The turbine housing may be
routed to include an oil and coolant supply, fed by a supply line
420.
[0048] Compressor 60 includes compressor housing 335, a compressor
collector, an impeller, and an air inlet. The compressor impeller
may be coupled to turbine 62 via shaft 160. The flow of exhaust gas
though turbine 62 may drive rotational movement of drive shaft 160,
which in turn drives the impeller to rotate. The air inlet delivers
air to compressor 60, which is then compressed by compressor 60.
Compressed air is then delivered back to intake manifold 44 through
a series of conduits as described above and depicted schematically
in FIG. 1.
[0049] Turbocharger assembly 300 is depicted as having a single
turbine and a single turbine scroll. In another example,
turbocharger assembly 300 may include more than one turbine and
more than one scroll, for example a dual-scroll turbine.
Turbocharger assembly 300 is depicted as having a single
compressor, but may include more than one compressor. In an example
system with more than one turbine, the turbines may have concentric
shafts that drive a single compressor or multiple compressors. In
another example, a supercharger may also be included in the vehicle
system.
[0050] Turning to FIGS. 5A-5B, an exhaust manifold 46 for a 4
cylinder engine is shown in accordance with the present disclosure,
which may be incorporated into the engine configurations of FIGS.
1-4. Exhaust manifold 46 may be incorporated into cylinder head
175. In one example, the engine may have a firing order of 1-3-4-2.
In this example, it may increase the efficiency of exhaust gas to
the turbine by separating the exhaust gas pulses such that
cylinders 1 and 4 are coupled together and cylinders 2 and 3 are
coupled together. In one example, cylinders 1 and 4 are coupled to
a first inlet of turbine 62 and cylinders 2 and 3 are coupled to a
second inlet of turbine 62. In this configuration, the exhaust gas
expelled into the manifold may be less likely to backflow into the
cylinders
[0051] As depicted in FIGS. 5a-b, cylinder 1 may include exhaust
valves coupled to exhaust ports 47a and 47b. Similarly, cylinder 2
may include exhaust valves coupled to exhaust ports 47c and 47d,
cylinder 3 may include exhaust valves coupled to exhaust ports 47e
and 47f, and cylinder 4 may include exhaust valves coupled to
exhaust ports 47g and 47h. Exhaust ports 47a and 47b may merge at
junction point 311a to form exhaust duct 310a. Similarly, exhaust
ports 47c and 47d may merge at junction point 311b to form exhaust
duct 310b. Exhaust ports 47e and 47f may merge at junction point
311c to form exhaust duct 310c, and exhaust ports 47g and 47h may
merge at junction point 311d to form exhaust duct 310d. Exhaust
runners 310a and 310d may further merge at a junction point 312a
that is downstream of junction points 311a and 311d. Merging at
312a in this fashion combines the exhaust flows of cylinders 1 and
4 into exhaust output duct 315a. Exhaust output duct 315a becomes a
sector of exhaust manifold 46 which feeds turbine 62. Similarly,
Exhaust runners 310b and 310c may further merge at a junction point
312b that is downstream of junction points 311b and 311c. Merging
at 312b in this fashion combines the exhaust flows of cylinders 2
and 3 into exhaust output duct 315b. A wastegate 26 actuated by
wastegate actuator 150 may be positioned in one or more of exhaust
ducts 310a, 310b, 310c and 310d, or positioned in one or more of
exhaust output ducts 315a and 315b.
[0052] Merging the exhaust from cylinders 1 and 4 and cylinders 2
and 3 in this fashion may allow for exhaust pulses to be separated
within the exhaust ports and may increase transient response and
decrease the amount of energy lost from the exhaust gas. In the
example where turbine 62 is an axial turbine, it may be possible to
achieve pulse separation from exhaust valves all the way up to the
point where the exhaust enters the turbine by forming exhaust
output duct 315a in the shape a half-circle and forming exhaust
output duct 315b in the shape of a half-circle complimentary to the
half-circle of exhaust output duct 315a.
[0053] Exhaust output ducts 315a and 315b may direct exhaust gas to
turbine inlet ports 515 and 520, respectively. In the example
depicted in FIG. 5B, turbine inlet ports 515 and 520 are positioned
such that a circle or circular shape that is within 10.degree. of a
circle is formed. The space 525 between exhaust exit ports may thus
also be a circle or circular shape that is within 10.degree. of a
circle. Space 525 may be a cooled portion of the cylinder head
material, for example aluminum. In this example, turbine inlet
ports 515 and 520 may also include elements as needed to interact
with stator 322 and rotor 325. In the example shown, the two
semi-circular annular regions 515 and 520 may be spaced apart from
one another via a separation region 530 that is contiguous with
ends of turbine inlet ports 515 and 520. The separation region may
be formed of a cooled portion of the cylinder head material. As
shown, two symmetric semi-circular outlets are shown, with
symmetric separation regions. However, asymmetric configurations
may also be used. The outlets may be steered to achieve a turbine
incidence angle most favorable for the specific turbine used. In
some examples, there may be more than 2 turbine inlet ports. For
example, there may be a turbine inlet port for each engine
cylinder.
[0054] As shown in FIG. 5A, the particular shape of the exhaust
manifold ports and convergence areas may first turn upward (with
regard to vertical being parallel to a cylinder's central axis),
and then bend back to a downward exit after the exhaust gasses have
been merged. In this way, advantageous exhaust flow can be
generated in combination with the engine firing order so that the
two semi-circular annular exhaust outlets can feed the axial
turbochargers input together. Other exhaust duct geometries are
possible to achieve pulse separation and correct velocity and angle
for the turbine inlet. For example, each cylinder may be coupled to
an individual exhaust port, exhaust duct and exhaust outlet duct.
In a 4-cylinder engine, there would thus be four exhaust outlet
ducts. The exhaust outlet ducts may be configured with a
quarter-circle outlet, the four outlets arranged in a complementary
fashion to form an annular outlet leading to the exhaust gas
collector or turbine inlet. Similar configurations may be utilized
for 6 or 8 cylinder engines.
[0055] The systems depicted in FIGS. 1-5B may enable one or more
systems. For example, a system comprising: a cylinder head having a
first and second exhaust duct separately coupled to first and
second groups of cylinders, each of the first and second exhaust
ducts leading to an exhaust driven turbine mounted inside the
cylinder head on a bearing, the bearing located within a bearing
housing supported by the cylinder head. The cylinder head may
further comprise cooling passages adjacent the turbine and a
wastegate gas passage. The turbine may be an axial, mixed flow or
radial turbine. The turbine may include one or more stages, and the
stages may include one or more stator stages. The stator stages may
be unique vanes or may be part of the cylinder head. Outlets of
each of the first and second exhaust ducts may form a semi-circular
cross-sectional coupling with a gas collector of the turbine. The
two semi-circular cross-sections of each of the first and second
outlets may be positioned relative to one another to form an
annular combined outlet. The system may further comprise at least a
third exhaust duct separately coupled to a third group of
cylinders. Each of the groups of cylinders may comprise one
cylinder, and each of the exhaust ducts may couple to a gas
collector of the turbine. The exhaust ducts may have arc-shaped
outlets that may combine to form an annular combined outlet.
[0056] In another example, A turbocharged engine comprising: a
cylinder head forming two or more exhaust ducts, each with an
outlet terminus at a turbine wheel or collector, an opening of the
outlet terminus of a first exhaust duct being a semi-circular
annular shape within 5.degree. of a half-circle and an opening of
the outlet terminus of a second exhaust output line being a
semi-circular annular shape within 5.degree. of a half-circle, the
outlet termini positioned opposite one another to form a circular
annulus. The exhaust duct may take the form of a variety of other
configurations. The cylinder head may include exhaust ports for two
or more engine cylinders. The engine cylinders may be placed in an
inline, opposed or V configuration. The turbocharged engine may
further comprise an axial turbine at least partially rotatably
mounted in the cylinder head. Rotor and stator stages of the axial
turbine may be positioned in the cylinder head. The first exhaust
duct may be coupled to outer engine cylinders, and the second
exhaust duct may be coupled to inner engine cylinders. The cylinder
head may further comprise a wastegate passage. The turbine may be
coupled to one or more compressors via a common shaft.
[0057] The systems depicted in FIGS. 1-5B may enable one or more
methods. For example, a method, comprising: combining, in a
cylinder head, exhaust gas from inner inline cylinders of an engine
to a first semi-circular annular exit; combining, in the cylinder
head, exhaust gas from outer inline cylinders of an engine to a
second semi-circular annular exit positioned opposite the first
semi-circular annular exit; and directing exhaust gas out of the
first and second exits through an axial turbine with bearings
mounted in the cylinder head. The axial turbine may be coupled to a
radial compressor through a common shaft. The method may further
comprise adjusting a wastegate valve to adjust flow through a
wastegate line positioned in the cylinder head.
[0058] It will be appreciated that the configurations and routines
disclosed herein are exemplary in nature, and that these specific
embodiments are not to be considered in a limiting sense, because
numerous variations are possible. For example, the above technology
can be applied to V-8, I-4, I-6, V-12, opposed 4, and other engine
types. The subject matter of the present disclosure includes all
novel and non-obvious combinations and sub-combinations of the
various systems and configurations, and other features, functions,
and/or properties disclosed herein.
[0059] The following claims particularly point out certain
combinations and sub-combinations regarded as novel and
non-obvious. These claims may refer to "an" element or "a first"
element or the equivalent thereof. Such claims should be understood
to include incorporation of one or more such elements, neither
requiring nor excluding two or more such elements. Other
combinations and sub-combinations of the disclosed features,
functions, elements, and/or properties may be claimed through
amendment of the present claims or through presentation of new
claims in this or a related application. Such claims, whether
broader, narrower, equal, or different in scope to the original
claims, also are regarded as included within the subject matter of
the present disclosure.
* * * * *